Thermostatic device



Aug. 12, 1930. w. H. PASCOE ET AL 1,772,570

THERMOSTATIC DEVI CE Filed May 28, 19 26 Patented Aug. 12, 1930 UNITED STATES.

PATENT OFFICE WILLIAM H. PASCOE AND JOHN W. TATTEB, OF CHICAGO, ILLINOIS THERMOSTATIC DEVICE Application filed May 28, 1926. Serial No. 112,413.

Our invention relates to thermostatic devices and particularly to thermostatic devices controlled by pilot lights or the like.

The invention has among its other objects the production of devices of the kind described and which are convenient, compact, durable, efiicient and saitsfactory for use wherever found applicable.

A particular object of the invention is to provide an improved device of the kind described which functions quickly when the temperature rises or falls a predetermined amount. K

Another particular object of the invention is to provide a device of the kind described which functions positively.

Still another articular object of the invention is to provide a device of the kind described which is simple in construction and is extremely dependable.

One form of the invention is embodied in oil burning apparatus in which vaporized oil issuing from a nozzle is ignited from a large pilot light, the large pilot light being supplied with gas from a gas producing lant or the equivalent. The large ilot light is ignited from a smaller pilot ight whenever the oil burning apparatus is set in operation, the smaller pilot light being su plied with gas from the same source as the arger pilot light. An electric motor forming art of the apparatus for supplying vaporize oil to the burner is controlled by a thermostatic device comprising a plurality of tubes con- 5 taining mercury or the equivalent, the tubes of mercury being so arranged and mounted with respect to electrical contacts that when the smaller ilot light is burning the motor circuit may e closed, and when the smaller pilot light ceases to burn, the mercury in one of the tubes contracts and'the device moves into a position wherein it opens the motor circuit.

Many other objects and advantages of the construction herein shown and described will 1 be obvious to those skilled in the art from the disclosure herein given.

To this end our invention consists in the novel construction, arrangement and combination of parts herein shown and described and more particularly pointed out in the. claims.

In the drawing, wherein like reference characters indicate like or corresponding parts:

' Fig. 1 is a somewhat diagrammatic view of apparatus embodying the invention; and

Fig. 2 is a section taken substantially on line 2--2 of Fig. '1, an electric circuit for controlling the motor shown in Fi 1 being illustrated diagrammatically in ig. 2.

In the drawing we have shown a preferred form of the invention embodied in oil burning apparatus, but it is to be understood that we are limited to this use only to the extent indicated in the ap ended claims.

Referring to the diawin and particularly to Fig. 1 for the present, t e reference character 1O designates a nozzle or burner projecting into a fire box 11 of a furnace, a 7

boiler or the equivalent. It will be noted that the burner 10 projects through an aperture 12 formed in a door 13 provided for the firebox. A pipe 15 connects the burner 10 with a compressor 16 which is mounted upon any suitable support and is preferably connected directly to an electric motor 17. Also voperatively connected to the electric motor 1 1s a ump 18, the intake of which is connected y a pipe 19 to a tank (notshown) and the outlet of which is connected by a i e 20 to the tank. The tank is adapted to hold a supply of oil. Piping 22 connects the pipe 20 with the compressor 16. The above described apparatus resembles, and functions substantially in the same manner as, that shown in U. S. Letters Patent No. 1,382,223 dated June 21, 1921, and is adapted to supply vaporized or atomized oil to the burner 10. It is to be understood that the details of the apparatus for supplying atomized or vaporized fuel to the burner 10 do not form a part of this'invention.

An aperture 24 formed in the door 13 below the aperture 12 permits a relatively large pilot light 25 to project its flame into the fire box in close proximity to the flame orifice of the burner 10, the pilot light 25 being so positioned that gas issuing from its flame orifice may be ignited by the flame of a relatively 101 small pilot light 27. As illustrated in Fig. 1, the pilot lights 25 and 27 are supplied with gas trom a gas'producing plant (not shown) or the equivalent through a pipe 29. The pipe 29 is connected to the pilot light 27 through a pipe 30, and the pipe 29 is con nected to the pilot light 25 through a valve (not shown) operatively connected to a diaphragm (not shown) mounted in a casing 32. A pipe 34 connects the pipe 15 with the interior of the casing 32 and the construction is such that when the motor 17 is in operation and a predetermined pressure obtains in the pipe 15 and therefore in the pipe 34 and the interior of the casing 32, the valve (not shown) will be opened so that gas may flow through the pipe 29 to the burner 25. The flow of gas through the pipe is preferably controlled by a manually operable valve 35.

The pilot light 27 projects into a housing 37 mounted upon the door 13 and mounted within the housing is a thermostatic device which is designated generally by the reference character 39. its best shown in Fig. 2, the thermostatic device 39 preferably comprises a substantially central metallic block 41, or the equivalent, mounted to oscillate about a knife edge pivot 42 projecting from the wall of the housing. Secured to the block 41 are two oppositely extending metallic tubes 44 and 45, which hold quantities of mercury. 46 or the equivalent. It will he noted that each tube 44 and is enlarged at one end to provide a chamber 48. The purpose of this construction will presently appear.

As indicated in Figs. 1 and 2, the thermostatic device 39 is arranged in such manner within the housing 37 that flame issuing from the pilot light 27 will burn in close proximity to the free end of the tube 45. Carried by the free end of the tube 44 are metallic con tacts 50 and 51 adapted to engage contacts 53 and 54, respectively, the contacts 53 and 54 being mounted within the housing 37 and being electrically insulated therefrom in any suitable manner.

In Fig. 2 we have diagrammatically illus trated an electrical circuit whereby the thermostatic device 39 controls the operation of the motor 17 At 56 and 58 we have indicated mains which are connected to any suitable source (not shown) of electrical energy. The mains 56 and 58 may be operatively connected through a switch 57 to conductors 60 and 61, respectively, the conductor 61 being directly connected to one terminal of the motor 17. The conductor 60 is connected to a contact 63 engageable by a metallic armature 64 which is connected to the other terminal of the motor 17 by a conductor 66. Obviously, when the contact 63 is engaged by the armature 64, and the switch 57 is in its closed position, current may flow from the conductor 56 through the conductor 60, the contact 63, the armature 64, the conductor 66, the motor 17, the conductor 61 and back through the conductor 58. This will cause the motor 17 to drive the compressor 16 and the pump 18, and the burner 10 will be supplied with vaporized or atomized fuel. The armature 64 is controlled by magnets 68 and 69, the magnets being so arranged that when the magnet 69 is energized the armature 64 is held in engagement with the contact 63 and when the magnet 68 is energized the armature 64 is held in a position wherein it does not engage the contact 63.

At 71 we have indicated diagrammaticall a conventional thermostat having contact points 72 and 73 engageable by a switch element 74, the construction of the thermostat being such that the switch element 74 is moved, into engagement with the contact 73 at a predetermined temperature and at a higher predetermined temperature the switch element is moved into engagement with the contact 72. It is understood, of course, that the thermostat 71 is adapted to be mounted upon the wall of a room which is heated by the apparatus shown in Fig. 1 and that it controls the apparatus inv such manner that the temperature in the room remains substantially constant.

The metallic block 41 is electrically con nected tothe conductor 61 and the contact 53 is electrically connected to the contact 72 and to one terminal of the winding of the magnet 68, the other terminal oi the magnet 68 being connected to the conductor 60. The contact 54 is electrically connected to the switch element 74 and the contact 73 is electrically connected to one terminal of the winding of the magnet 69, the other terminal of this winding being electrically connected to the conductor 60.

The thermostatic device 39 is so constructed and balanced that it occupies the position wherein it is shown in dotted lines in Fig. 2 when the pilot light 27 is not in operation. The contact 50 of the metallic tube 41 is then in engagement with the contact 53 and electrical current will fiow as follows: from the main 56 through the conductor 60, the wind ing of the magnet 68, the contacts 50 and 53, the tube 44, the block 41 and back through the main 58. This will energize the magnet 68 and the circuit for the motor 17 will be held open. Now, if the pilot light 27 is ignited, the heat of its flame will cause the mercury 46 in the tube 45 to expand and the center of gravity of that part of the thermo-- static device 39 disposed to the right (Fig. 2) of the pivot 42 will move toward the pivot, the arrangement being such that the thermostatic device moves quickly into the position wherein it is shown in full lines in Fig. 2. It will be noted that the contact 51 of the tube 44 then engages the contact 54. Assuming that the switch element 74 engages the contact 73, electrical current will flow as 'III follows: from the main 56 through the wind room in which the thermostat 71 is posiing of the relay 69, the contact 73, the switch element 74, the contacts 51 and 54, the tube 44, the block 41 and back through the conductor 61 and the main 58. The magnet 69 will then be energized and it will hold the armature 64 in engagement with the contact 63 so that the motor 17 may operate continuously until its circuit is again opened. Assuming now that the thermostat 71 functions to bring itsswitch element 74 into engagement with the contact 72, electrical current will cease to flow through the magnet 69 and will flow, instead, as follows: through the main 56, the conductor 60, the winding of the magnet 68, the contact 72, the switch elements 74, the contacts 51 and 54, the tube 44, the block 41 and back through the conductor 61 and the main 58. This will cause the magnet 68 to hold the armature 64 out of engagement with the contact 63 and the motor 17 will not operate.

Briefly, the operation of the above described apparatus and circuit is substantially as follows: Assuming that the contact 73 is engaged by the switch element 74 and that the flame of the pilot light 27 has expanded the mercury 46 in the tube 45 sufiiciently that the thermostatic device 39 occupies the position wherein it is shown in full lines in ig. 2, the switch 57 may be closed to set the motor 17 in operation. As above described, the magnet 69 will then be energized to hold the armature 64 in engagement with the contact 63 so that current will flow through the main 56, the conductor 60, the contact 63,the armature '64, the conductor 66 and back through the motor 17.to the main 58 by way of the conductor 61. When the motor 17 is thus set in operation a mixture of air and vaporized or atomized oil is delivered to the nozzle under pressure, which pressure causes the diaphragm (not shown) to open the above described valve (not shown) whereupon gas flows from the pipe 29 to the pilot light and is ignited by the flame of the pilot light 27. The flame of the pilot light 25 ignites the vaporized or atomized oil issuing from the burner 10. If, for any cause, accidental or otherwise, the flame of the pilot light 27 is extinguished, themcrcury 46 in the tube contracts and the thermostatic device 39 moves into the position wherein it is shown in dotted lines in Fi 2.

. This causes the magnet 69 to be deenerglzedand simultaneously causes the magnet 68 to be energized whereupon the armature 64 is- 'phragm (not shown) will close the valve (not shown) and the pilot light 25 will be extinguished. v If the temperature in the tioned rises above a predetermined value, the switch element 74 is disengaged from the contact7 3 and moved into engagemnet with the contact 72 and the motor circuit is opened, as explained above. Of course, if the thermostat device 39 is in the position wherein it is shown in full lines in Fig. 2 and the switch element 74 returns to the contact 7 3 because the room temperature is lowadvantageous, as the device remains balanced when both tubes are equally subjected to a rise or fall of temperature. Thus the mercury in each tube expands from the heat of the fire box and normally maintains the device in a predetermined balanced position when the pilot light is extinguished and permits the device to quickly assume another position when the pilot light becomes functionally operative. Obviously, atmospheric conditions will not affect the efliciency of the device, as both quantities of mercury will expand and contract substantially simultaneously when there is a change in suchconditions.

. In some instances we may prefer to dispense with mercury, or the equivalent, in the tubes 44 and 45 and so balance them that the thermostat device occupies the position wherein it is shown in full lines when the pilot light 27 is not functioning. If the positions of the contacts 53 and 54 are then reversed, the apparatus will function in substantially the same manner as set forth above,

it being obvious that when the tube 45 is subjected to the flame of the pilot light 27 it will elongate and its center of gravity will move away from the pivot 42, whereupon the thermostatic device will move into the position wherein it is shown in dotted lines in Fig. 2.

7 Having thus described our invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of our invention; hence we do not wish to be understood as limiting ourselves to the exact form, construction, arrangement and combination of parts herein shown and described or uses mentioned.

What weclaim as new and desire to secure by Letters Patent is:

1. A pivotally supported thermostatic dea vice comprising a pair of non-communicating normally balanced tubes, a quantity of mercury disposed in said tubes, and means for balancing said tubes and mercury.

2. In a device of the kind described, a pivot, oppositely disposed tubular members inclined toward and normally balanced about said pivot, an expansible fluid in each of said tubes, means disposed adjacent one of said tubes and cooperating therewith to control an electric circuit, and means disposed adjacent the other tube for changing the center of gravity of the liquid in said tube.

3. In a device of the class described, a pivotally supported thermostatic member comprising a pair of opposed normally balanced arms, one of said arms being adapted to shift its center of gravity independently of said other arm upon a variation of the temperature of said first'arm, whereby said member may be rotated about its pivot to perform a plurality of functions corresponding to various positions thereof. I

4. In a device of the class described, a pivotally supported thermostatic member comprising a pair of opposed normally balanced non-communicating chambered arms, one of said arms being adaptedto shift its center of gravity independently of said other arm upon variation of temperature of said first arm, whereby said member may be rotated about its pivot to perform a plurality of functions corresponding to various positions thereof.

5. In a device of the class described, a pivotally supported thermostatic member comprising a pair of opposed normally balanced non-communicating chambered arms, an expansible liquid occupying a portion of the space in said arms so that the center of gravity of one of said arms may be shifted upon the thermal expansion or contraction of the liquid therein, whereby said member may be rotated about its pivot to perform a plurality of functions corresponding to various positions thereof.

6. In a device of the class described, a pivotally supported thermostatic member com- :uwasvo prising a pair of opposed normally balanced non-communicating hollow arms of substantially fixed mass, one of said arms being adapted to shift its center of gravity independently of said other arm upon a variation of the temperature of said first arm, one of said arms-comprising an electrical conductor, means adjacent the pivot of said member and electrically connected to said conductor for contacting with an electric circuit, and means on said conductor for selectively contacting with electrical conductors spaced on opposite sides thereof, whereby said first named conductor may close one of a pair of circuits according to the direction of its oscillation about its pivot. v

In testimony whereof, we have hereunto signed our names.

JOHN W. TATTER.

WILLIAM H. PASCOE.

prising a pair of opposed normally balanced arms of substantially fixed mass, one of said arms being adapted to shift its center of gravity independently of said other arm upon a variation of the temperature of said first arm, one of said arms comprising an electrical conductor, means adjacent the pivot of said member and electrically connected to said conductor for contacting with an electric circuit, and means on said conductor for selec tively contacting with electrical conductors spaced on opposite sides thereof, whereby said first named conductor may close one of a pair of circuits according to the direction of its oscillation about its pivot.

72'. In a device of the class described, a pivo'tally supported thermostatic member com- 

